Elevator system



q cww 0 p il 26, 1949.

Filed Sept. 11,

BRAKE HOISTINGNOTO TRACTION su LOU NTE RWEIGHT HOISTING R0055 CAR N 1CAR DOOR H- BRUNS ELEVATOR SYSTEM MOTOR GENERA SET CROSbHEAD HOISTWAYooo LANDING BUTTON5 4 FLOOR -5TE E LTAPE STARTERS PANEL ISJ FLOOR FIGLI9 Sheets-Sheet 1 WM 1 03W INVENTOR ATTORNEY April 26, 1949. w. H. BRUNS2,468,289

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' Apl il 26, 1949. w. H; BRUNS ELEVATOR SYSTEM 9 Sheets-Sheet 9 l 2 5UllllllllllllllfiolllllvlflIIIIIIIIIIIIJIIIIIIWTIII]? 4wlllllillllllllllllllilllfiul a 4 1 I m mT wTl 2 I M ET E Rfilllllfllllllllllflg 5 3 mlllvllrllllmflvlllllllle J .2HIIIIIIIIIIIIIIIIIIIQ 3 4 .3 1D fi fl lww MT ET LH a H RHT LT 4 4EllilllfllllllllmflmlllllllgllIIIIIIIIIIIIE x v M 8 9 R llllllwlfimWall: SP VL= T E L= 5 ll 2 Y 4wlllllllllllllllfimlyfllllllllllllllllllilglllalllia m l...MIIIIILTIIIIIIIIIIIIIIIIL. z 4 lllliffirlllllllllllllllllm WM Haw GMINVENTOR FIGA-s ATTORNEY Patented Apr. 1949 I 2,468,289 ELEVATOR SYSTEMWilliam Henry Bruns,

Lincolndale, N. Y., asslgnor to Otis Elevator Company, New York, N. Y.,a. corporation of New Jersey Application September 11, 1946, Serial No.696,313

65 Claims.

The invention relates to elevator systems.

The invention is especially directed to elevator control systems inwhich the starting of the elevator car after each stop is under controlof an attendant in the car, while the stopping of the car is automatic,stops to discharge passengers being made in response to controls withinthe elevator car operated by the attendant as directed by thepassengers, and stops to take on passengers being made in response tocontrols at the floors operated by the intending passengers themselves.At intermediate floors, two controls are provided, one an up control foroperation by intending passengers desiring to be carried in the updirection and the other a down control for operation by intendingpassengers desiring to be carried in the down direction. With suchcontrol system applied to a plurality of elevator cars, the controls atthe floors the cars.

It is customary to utilize push buttons as these controls in the carsand at the floors. These push buttons when pressed close contacts tooperate floor relays to register calls, enabling the push buttons to bereleased. Also it is customary to utilize manually operable switcheswith contacts for other control operations such as closing the doors andstarting the car. There are certain advantages in exercising control ofcircuits electronically.

The object of the invention is to provide a control system forelevators, especially control systems of the above character, in whichcertain operations are effected or controlled electronically. 4

In carrying out the invention according to the preferred arrangement,electronic tubes are provided at the floors and arranged to be operatedin response to touch by intending passengers. Electronic tubes, one foreach floor, are also provided in the elevator car for operation inresponse to touch by the car attendant. These tubes, both in the car andat the floors, are cold cathode gas tubes with their circuits arrangedso that they break down in response to manual touch and remainconductive, thereby registering the call and enabling the touch to bediscontinued. When the call is answered the voltage between the anodeand cathode of the tube is reduced to below sustaining value and thetube goes out, cancelling the call. Similar controls are provided in thecars for controlling other operations such as starting the car, openingand closing the doors, running non-stop past floors for which calls areregistered from the floors are common to and changing the direction ofcar travel at intermediate floors. Certain of these controls, such asthe door close, start and reversal controls may be arranged so that thetube remains conductive only so long as the touch is continued or in thecase of the start control only until the car has started.

When a call is registered, the tube upon which the call is registereddirectly controls the call pick-up and call cancelling circuits and theinitiatlon of the stopping of the car. The invention will be describedas applied to a systeminwhichan up car answers a, down call at anintermediate floor when no up call is registered for that floor and nocall exists for a floor above and is then set for travel in the downdirection. This operation is usually termed highest call return. Theinvention'will also be described as applied to a system in which an upcar may be stopped at a. floor in response to a down call which hasremained registered for more than a predetermined length oitime, anoperation referred to as timed call preference. Here again, the tubesupon which the calls are registered directly control the highest callreturn and timed call preference circuits.

The electronic tube itself is utilized to provlde an illuminatedindication that the desired operation is being performed. In the case ofthe controls for registering calls, this advises the passengers and alsothe attendant in case of car calls, that the calls have been registered.In certain installations, elevators are arranged on both sides of thecorridors and it is considered desirable in such installations toprovide controls on both sides of the corridor at each floor. The systemwhich will be described provides for controls on both sides of thecorridors and the circuits are arranged so that the registration of acall by touching a control on either side of the corridor also elfectsillumination of the tube of the corresponding control on the other sideof the corridor. Thus visual indication that the call is registered isprovided on both sides of the corridor.

It sometimes happens that a car call is registered for a floor when infact no stop is desired there to discharge a passenger. The system alsoprovides for cancelling this call by touch.

The electronic tubes of these various controls may be broken down eitherby touching the tube envelope or an operating member such as a buttonpreferably immovable connected to the tube envelope. The latterarrangement is preferred as it has certain advantages and as passengersand attendants have grown accustomed to manipulating buttons. Thisbutton may be of conducting material having a high or low resistance ormay be of a material having a high dielectric constant. Also the tubeand button may be shielded against unwanted operation.

Features and advantages of the invention will be gained from-the abovestatements and from the following description and appended claims.

In the drawings:

Figure 1 is a simplified schematic representation of an installation oftwo elevators in accordance with the invention.

Figures 2, 3 and 4 taken together constitute a simplified schematicwiring diagram of the power and control circuits for one of theelevators of Figure l, certain of the circuits being common to theelevators.

Figures 2s, 3s and 4s are key sheets for Figures, 2, 3 and 4, showingthe electromagnetic switches in spindle form; and Figures 2a. and 3ataken together are the control circuits for another of the elevators ofFigure 1, corresponding to those of Figures 2 and 3 for one elevator.

For a general understanding of the invention, reference may be had toFigure 1, wherein various parts of the system, chosen to illustratetheprinciples of the invention, are indicated by legend. Two elevators areillustrated and are indicated as serving four floors. Each elevator caris raised and lowered by means of a hoisting motor. This motor drives atraction sheave over which pass the hoisting ropes for the car andcounterweight. provided and is applied to effect the final stoppingoperation and to hold the car when at rest.

Each elevator car is provided with a car operating panel on which arelocated a plurality of controls for operation by the car attendant.These include a plurality of call registering controls, one for eachfloor, hereinafter termed car buttons, 2.- start control hereinaftertermed start button, door controls hereinafter termed door close buttonand door open button, a non-stop control hereinafter termed non-Stopbutton and reversal controls hereinafter termed up reversal button anddown reversal button. These buttons are shown in th wiring diagrams andwill be referred to later.

The call registering controls at the floors hereinafter termed landingbuttons are illustrated as arranged in two risers as indicative of aninstallation in which elevators are arranged in groups on each side ofthe corridors. An up landing button and a down landing button areprovided in each riser at each intermediate floor. One landing button isprovided in each riser at each terminal floor.

Referring now to the wiring diagrams, the various control and powercircuits are illustrated diagrammatically. Figures 2 and 3 show callregistering, call pick-up, highest call, stop initiating and callcancelling circuits for four floors as applied to one elevator. Figure 4shows additional control circuits and the power circuits for thiselevator. When applied to a plurality of elevators, the landing callregistering circuits and certain circuits associated therewith arecommon to the elevators, and circuits corresponding to those of Figures2, 3 and 4 individual to the one elevator are provided for the otherelevators, as will be seen from Figures 2a and 3a; circuits for a secondelevator corresponding to those of Figure 4 not being shown but beingthe same. The

same reference characters as employed in Fig- An electromechanical brakeis g ures 2 and 3, but with the letter a appended thereto, are appliedto the corresponding parts in Figures 2a and 3a.

In the description which follows, unless otherwise indicated, referencewill be to th circuits of Figures 2, 3 and 4. A simplified controlsystem has been illustrated because it facilitates disclosure of anapplication of the invention. ,It is.

understood that other control and safety elements may be added in makingup the system and that such system is subject to many variations. Theelectromagnetic switches employed in the system illustrated aredesignated asfollows:

BK, brake resistance switch DC, door close switch DD, down directionswitch m, direction holding switch DGX, auxiliary direction switch DO,door open switch E, speed switch ms, auxiliary speed switch H, field andbrake switch HJ, highest call switch HLS, highest call light switch HR,highest call reversal switch KR, runni switch PM, pawl magnet SO,operating sequence switch UD, up direction switch XA, speed switchtiming relay XY, landing call non-cancelling switch Throughout thedescription which follows these letters will be applied to the coils ofthe above designated switches. Also, with reference numerals appendedthereto, they will be applied to the contacts of these switches. Thecoil of the electromechanical brake is similarly designated as BR andcontacts operated by the brake are designated as BRl. Letters are alsoemployed to designate other switches and elements of the control system.In certain instances, such as the case of the landing buttons, theseelements are provided for the floors. In such cases, differentiation asto floors is made by appending to the letters numerals corresponding tothe floor numbers with the letter I used for the upper terminal insteadof a numeral.

The circuits are shown in straight or acrossthe-line form in which thecoils and contacts of the various switches are separated in such manneras to render the circuits as simple and direct as possible. Therelationship of these coils and contacts may be seen from Figures 2s, 3sand 4s, where the switches are arranged in alphabetical order, and wherethe coils and contacts are positioned on spindles in horizontalalignment with the corresponding elements of the wiring diagram. Theelectromagnetic switches are illustrated in deenergized condition withdirection holding switch DG. which is a latching switch, in unlatchedcondition.

Referring now especially to Figures 2 and 3,

the up landing buttons are designated U while the down landing buttonsare designated D. The landing buttons of one riser are marked with aprime to distinguish them from those of the other riser. The landingbuttons in a plural elevator installation, whether arranged in a singleor double riser, are common to all the elevators. The car buttons aredesignated 0.

The start button is designated SB. The door close and door open buttonsare designated DCB and D03 respectively. The non-stop button isdesignated N83. The up reversal and down reversal buttonsare designatedURB and DRB respectively.

A plurality of additional touch control electronic tubes, one for eachfloor above the lower terminal, are provided in the elevator car on thecontrol panel for manually cancelling registered car calls for thecorresponding floors when stops are not desired for passenger discharge.These controls which will hereafter be termed car call cancellingbuttons are designated CC. A similar touch control electronic tube isprovided for the non-stop button, this control being termed a nonstoprelease button and designated NSRB.

The electronic tubes of the touch buttons so far referred to are coldcathode gas tubes and preferably of the type having a wire anodeextending to Within a short distance of the glass envelope of the tube,such as the RCA 1C21 and Western Electric 313C. These tubes are arrangedto be touched adjacent the anode or, where a fixed button is provided tobe touched, the button is connected to the tube envelope adjacent theanode. Suitable arrangements are disclosed in the copending applicationsof William Henry Bruns, namely, application Serial No. 604,185, filedJuly 10, 1945, application Serial No. 769,- 035, filed August No. 31,293filed June 5, 1948. The tubes of the type mentioned are three elementtubes having an anode, a cathode and a control electrode, designated forlanding button D3 for example an AN, CA and GD respectively. The controlelec-- trode is utilized for controlling the corresponding tube acrossthe corridor. When a single riser of landin buttons is utilized thecontrol electrodes are connected to the cathodes. This is done in caseof the car buttons for floors above the first floor, car call cancellingbuttons, start button, non-stop buttons, reversal buttons and door openbutton, and as a consequence the control electrodes are not indicated inthe circuits. Also tubes having only two electrodes may be employed insuch instances.

Other electronic tubes are employed in the system. These include tubesarranged in call pick-up and stop initiating circuits. Two of thesetubes are provided, one for car calls designated CCP and one for landingcalls designated LCP Also a tube is provided in the circuits forautomatically cancelling calls registered by the landing buttons whenthese calls are answered.

16, 1947 and application Serial- This will hereinafter be termed landingcall canceiling tube and designated LCC. Also a tube is provided in thehighest call return circuits which will be termed highest call returntube and designated HCR. Tubes CCP, LOP, LCC and HCR are preferably coldcathode gas tubes of the RCA 0A4G type.

TF2 is a tube utilized in the time preference circuits for the secondfloor. This tube is a thyratron such as the RCA 2050.

One or more position indicators are provided position indicator lamps,one for each floor, are utilized. These lamps are illustrated as glowdischarge tubes and are designated generally as PC. The car positionindicator may be located in the car or on the starters panel (see Figure1), or a car position indicator may be provided at each of theselocations.

Waiting passenger indicator lamps are provided for indicating the callsregistered by landing buttons, These lamps are illustrated as glowdischarge tubes and are designated generally as WPU for up calls and WPDfor down calls. The

waiting passenger indicator is common to all the elevators and isusually located on the starters panel, Figure l, in control systems ofthis character.

A plurality of rectifiers are provided which are designated generally asV. A considerable number of these rectifiers are for blocking the flowof appreciable current in one direction in direct current circuits.Certain of these direct current blocking rectifier-s, one for eachfloor, are in the circuits controlled by the car buttons and aredesignated VC. Certain other of these direct current blockingrectifiers, one for each intermediate floor, are in the highest landingcall circuits and are designated VHL. Certain others of the directcurrent blocking rectifiers, one for each pair of down landing buttonsand one for each pair of up landing buttons, are provided in theconnections from these landing buttons to the highest landing callcircuit. Those in the connections to down landing buttons are designatedVD and those in the connections to up landing buttons are designated VU.Selenium rectifiers have been found satisfactory in these circuits,Other rectifiers employed in the circuits will be referred to later.

A plurality of resistors are provided which are designated generally asR. Certain of these resistors serve as load resistors in theanodecathode circuits for the tubes of the car buttons and landingbuttons. The load resistors for the tubes of the car buttons aredesignated RC. The load resistors for the tubes of the up landingbuttons are designated RU while those for the tubes of the down landingbuttons are designated RD. Resistors are also provided in theanode-cathode circuits for the tubes of the car call cancelling buttons.These resistors serve as protective resistors and are designated RCC.Protective resistors are also provided in the circuits for the controlelectrodes for the tubes of the landing buttons.

These resistors for the tubes of the up landing buttons are designatedRUG and for the tubes of the down landing buttons are designated RDG,with differentiation as to side of corridor the same as in the case ofthe landing buttons. Protective resistors are also provided in thecircuits for the waiting passenger indicator lamps. These resistors forthe up waiting passenger indicator lamps are designated RWU and thosefor the down waiting passenger indicator lamps are designated RWD. Aprotective resistor is provided for the car position indicator lamps.This resistor is common to these lamps and is designated RFC. Equalizingresistors are provided in the anode-cathode circuits for the tubes ofthe landing buttons to enable the tubes of the corresponding buttonsacross the corridor to be operated in parallel. These resistors for thetubes of the up landing buttons are designated RUE and those for thetubes of the down landing buttons are designated RDE, withdiflerentiation as to side of corridor the same as in the case of thelanding buttons. RURZ is a protective resistor for the anodecathodecircuits for the tube of up reversal button URB while RDRZ is aprotective resistor for the anode-cathode circuits for the tube of downreversal button DRB. RDOI are protective resistors for the anode-cathodecircuits for the tube of door open button DOB. RNSR is a protectiveresistor for the anodecathode circuit for the tube of non-stop releasebutton NSRB. RLCP is a protective resistor for the anode-cathode circuitfor tube LCP, this resistor also serving as a protective resistor forthe and RDOI accuses anode-cathode circuitfor tube COP. RDCP is aprotective resistor in the circuit for the control electrode for thetube of door close button DCB while DRCT is a resisor in a circuit to!connecting this electrode to the cathode of this tube. RCGP is aprotective resistor in the circuit for the control electrodes for thetube or car button Cl for the first floor while RCGT is a resistor in acircuit for connecting this electrode to the cathode of this tube.RL'PP, RCPP, RHCP and RLGP are protective resistors in the circuits forthe control electrodes for tubes LCP, GOP, HCR and LCC respectively.RLPT, RCPT, RHCT and RLCT are resistors in circuits connecting the control electrodes and cathodes of tubes lJCP, CCP, HCR and LCCrespectively. REC is a load resistor in the anode-cathode circuit fortube LCC while resistors RLCDl and RLCD2 taken together constitute a.voltage divider for determining the voltage applied to the anode-cathodecircuit oi this tube. R58 is a resistor in a circuit having to do withenabling the attendant to discontinue the touch of the start buttonwithout interrupting the running of the car. RACE is a resistor in thecircuit for automatically cancelling car calls when these calls areanswered which enables load resistors of smaller capacity to be utilizedfor the car buttons. Other resistors employed in the circuits will bereferred to later.

A plurality of condensers are provided which are designated generally asQ. Certain of these condensers designated QC are in the call cancellingcircuits for the car buttons; Certain other of r these condensers are inthe circuits for the tubes of the landing buttons. Those for the uplanding buttons are designated QU and those for the down landing buttonsare designated QD, with difierentiation as to side of corridor the sameas in the case of the landing buttons. QCC is a condenser in a circuitcommon to the car call cancelling buttons and having to do withextinguishing the tube of the car call cancelling button when one istouched to manually cancel a car call.

QNSR is a condenser which serves a similar pur pose for the non-stoprelease buttons. QNS, QPM, QDO, QDR and QUR are voltage absorbingcondensers to prevent unwanted firing of tubes due to voltage surges aswhen the anode-cathode circuits for the tubes are established. CondenserQCU and inductance IC serve to prevent unwant ed firing 0f the tubes ofthe car buttons and our call cancelling buttons when switch IS isclosed. RURi is a resistor for protecting the tube of button URB fromthe collapse of condenser QUR when the tube breaks down. Resistor RDRGserves the same purpose for the tube of button DRE, while coil D0 servesthe same pu p se for the tube of button DOB and coil PM serves the samepurpose for tubes 00? and LCP, assisted in the case of tube CCP byresistor RC0? and in' the case of tube LCP by resistor RLCP. Othercondensers employed in the circuits will be referred to later.

Mechanism actuated in accordance with movement of the elevator car isutilized in the electronic controlcircuits of each elevator. Suchmechanism may be in the form of a floor selector asindicated inFigure 1. Each selector is driven preferably by means of a tape attachedto the car and counterweight and having teeth thereon by a chain andsproclsehin turn driven from the shaft upon which the driving wheel ismounted, thus moving the crosshead in accordance .with movement of thecar. The crosshead carries a carriage upon which is mounted mechanismfor controlling the call pick-up, highest call stop initiating and callcancelling circuits. Mechanism is also mounted on the carriage forcausing, when a stop is initiated tor a floor, slow down to begin at acertain distance from the floor and for causing the car to be brought toa stop as it arrives at the floor. The carriage is advanced from aneutral position with respect to the crosshead in starting the car andis brought to a stop after a certain amount of movement. Thereafter thecarriage moves with the crosshead which moves with the car. Whencircuits are set up to initiate a stop the carriage is brought to astop. This may occur either during the advance for installations of overa certain speed or during movement of the carriage with the crosshead.The crosshead thereafter takes up the advance of the carriage so thatwhen the car comes to a stop, the carriage is again in neutral. Thisrelative motion of the carriage and crosshead is utilized to control theslow down and stopping of the car.

l The advance of the carriage is effected by means of a torque motorwhich will hereinafter be termed the advancer motor. The circuits ofthis motor appear in Figure 4 where the motor is designated AM.Energization of the advancer motor is controlled by contacts operated bythe pawl magnet PM. The circuits for this magnet appear in Figures 2 andd. coils, one an operating coil and the other a reset coil. Whenoperated, the magnet is latched in for engaging teeth on the selectordriving wheel.

It comprises a crosshead which is driven by a operated condition as by apermanent magnet core and remains so until the reset. coil is energized.The pawl magnet controls the extension and retraction of pawls carriedby the carriage for cooperation with stopping lugs. A stopping lug isprovided for each floor and is arranged on a floor bar, these floor barsbeing spaced in accordance with the distance between the floors forwhich the lugs are provided. The pawl magnet is energized in thestarting operation to effect the retraction of the pawls and in doing soit engages contacts to efiect the energization of the advancer motor.The advancer motor in advancing the carriage also efi'ects theengagement of selector switches appearing in Figures 3 and 4 anddesignated 31S, 2L8 and lLS. When a stop is initiated, the pawl magnetreset coil is enersized to release the latch. This causes thedeenerglzation of the advancer motor and the extension of the pawls forcooperation with the stopping lugs. The pawl for the direction in whichthe car is travelling engages the stopping lug for the fiooznfor whichthe stop is initiated, bringing the carriage to a stop. The crossheadcontinues its movement and, due to the relative movement between thecrosshead and the carriage, effects the opening of selector switches318, 216 and iLS in sequence to eifect the slow down and stopping of thecar.

Travelling brushes are carried by a panel on the carriage to cooperatewith stationary contacts for the various floors arranged on the floorbars. Also a cam is provided on this panel for engaging hook switchesfor the various floors mounted on the floor bars. When the car isstopped at a floor, the brushes are in engagement with their cooperatingstationary contacts for that floor and This magnet has two the cam isengaged with the hook switch for that floor. Being on the advance panel,however, these brushes and cam are advanced in starting the car, arelatched in engagement with their contacts and hook switch for afloor bya pawl when a stop is initiated and are maintained in that condition asthe advance is taken up as thecar comes into the floor. A switch is alsocarried by the carriage to be actuated by trough shaped cams, one foreach floor, mounted on'the floor bars. A brush and a cam are mounted ona panel carried by the crosshead so as not to be advanced by theadvancer motor. This brush and cam are for engaging contacts and hookswitches mounted on the floor bars. These brushes, cams, stationarycontacts and hook switches are shown in the wiring diagram and occur forthe most part in Figure 2.

Referring first to Figure 2, the switch operated by the trough shapedcams has to do with initiating stops and is designated SI. The troughshaped cams with which this switch cooperates are designated generallyas TC. The cam carried by the crosshead which is not subject to theadvancer motor and the hook switches engaged thereby are in the carposition indicator circuits and automatic car call cancelling circuits.This cam is designated CX while the hook switches are designatedgenerally as HX. This cam is formed with, its leading edges ofinsulating material as indi-- cated. This causes a hook switch, whenengaged, to open its contacts before contact is made between the hookend of the switch and the donducting portion of the cam. The cam carriedby the advancer panel and the hook switches with which it cooperateshave to do with car call pick-up and the highest car call operations.This cam is designated CY while the hook switches are designatedgenerally as HC. This cam also has its leading edges formed ofinsulating material so that the hook switches are open before contact ismade with the current conducting portion of the cam. Also this cam is ofa length to cause, when its conducting portion is engaging a hookswitch, the lower insulating portion to open the hook switch next below.Two of the brushes carried by the advancer panel and the stationarycontacts with which they cooperate have to do with landing call pick-upand automatic call cancelling operations. This brush for up landingcalls is designated BU while the stationary contacts which it engagesare designated generally as SU. The brush for down landing calls isdesignated BD while the stationary contacts which it engages aredesignated generally as SD. No stationary contact is provided for thetop floor for engagement by brush BU. Another brush carried by theadvancer panel and the stationary contacts with which it cooperates haveto do with highest landing call circuits. This brush is designated BHLwhile the stationary contacts with which it cooperates are designatedgenerally as HL. Brush BHL is mounted on a lever for eflecting theseparation of contacts HLC when the brush engages a stationary contact.vThe stationary contacts SU, SD and HL are connected to the correspondingstationary contacts of the selectors for the other elevators. Thisconnection is effected by the wires designated generally as WU, WD andWH.

Referring now to Figure 4, another brush ADB carried by the advancerpanel is arranged to engage a stationary contact ALC at the first floor.They have to do with the direction circuits as will be explained later.The brush carried by the 10 crosshead so as not to be subject to theadvancer motor and the stationary contacts engaged thereby are shown inFigure 3 and have to dowith automatically changing the direction oftravel at the terminal floors. This brush is designated DB while thestationary contacts which it engages and which are provided at the firstand top floors are designated LTC and 'I'IC.

The source of power for the electronically controlled circuits,indicated principally at the top of Figure 2, is one capable ofproviding various values of direct current and alternating currentvoltages and combinations thereof. The feed lines of this source whichprovide direct current are designated generally as B with thedifferentiation made by appending numbers thereto indicative of thevalue and polarity of the voltage of the line with reference to thevoltage of the line designated solely as B which is taken as zero. Thevoltage values indicated are for electronic tubes of the types mentionedfor the particular circuits. The voltages provided by feed lines B+l50and 13-50 are taken directly from the source. The voltages provided byfeed lines designated B+l00, B+70 and B30 are obtained oil. voltagedividers RDVi and RDV2 respectively connected across feed lines B+150, Band 3-50. Another voltage divider RDB3 is connected across feed lines Band B+150 but subject to service switch IS. This is utilized to providevoltage for the lamps of the position indicator, the value of whichdepends on the type of lamps used. Certain of the alternating currentvoltages are illustrated as provided by transformers TFI, TF2 and TF3,which may have a primary common thereto instead of separate primaries.Connections are made from one side of the secondary of each transformerto certain ones of the direct current feed lines. The other side of thetransformer TFI is connected to a feed line designated ACI A tap on thesecondary of transformer TF2 is connected to a feed line designated AC2.A voltage divider RDV4 is connected from this tap to the other side ofthe secondary and a tap on this voltage divider is connected to a feedline designated AC3. A tap on the secondary of transformer TF3 isconnected to a feed line designated AC4. A voltage divider RDV5 isconnected from this tap to the other side of the secondary and a tap onthis voltage divider is connected to ground GR. For the particular tubesmentioned, the root mean square values of the alternating currentvoltages are:

110 volts from ACI to 3-50 60 volts from AC2 to B volts from AC3 to B150 volts from GR to B+70 volts from AC4 to B+70 For convenience, feedlines ACI, AC2, AC3 and AC4 are not extended down the sheets as in thecase of the direct current feed lines, but the connections are indicatedby applying the reference characters for these feed lines to thecircuits to which they are connected. In certain instances, connectionsto direct current feed lines are indicated in a similar manner. Also forconvenience, a transformer TF4, the secondary of which is connected incircuit with the control electrode of tube LCC, is shown at that point.The root mean square value of the voltage of this secondary is 40 volts.The voltage values enumerated may vary, some considerably.

For the above voltage values and for the types of electronic tubesspecified, the followin ohmic values of resistors and capacities ofcondensers in the electronic circuits have been found satisfactory.

Resistors Ohms RDOl, RDRl, RURl -4 100 ste t8 RmiiIaDxa R Ns-.'II .I1,000 RACC RDO2. 2:000 3,000 4,000 5,000 10,000 20,000 50,000 I 00,000100,000 200,000 300,000 400,000 1 meg. 2meg. 10 meg Condensers E53;

.02 .02 QDO, QDR, QUR

3.5 Q QCC,QCU,QNS,QN8B,QNBR 4 Pivr 8 Referring now also to Figure 4, anysuitable form of power supply may be provided for the elevator motor.One of the preferred arrangements is to employ a direct current elevatormotor and to cause current to be supplied to the motor at a variablevoltage, as from a driven generator in accordance with Ward-Leonard principles. Such an arrangement is illustrated in Figure 4 and the motorgenerator set is shown in Figure 1. It is to be understood that either adirect current or alternating current driving motor may be employed todrive the generator, depending upon the kind of power supplied to thebuilding and the character of the installation,

and that any suitable control arrangement therefor may be utilized. 4

When the generator is driven by an alternating current driving motor, anexciter which may be driven by the driving motor is employed to supplycurrent to the separately excited field windings of the supply generatorand the elevator motor and to the brake and the coils of the variouselectromagnetic switches of Figure 4. In such arrangement, the supplylines of Figure 4 would be connected to the exciter.

The armature of the generator is designated G,

its separately excited field winding being designated GF and its seriesfield winding GSF. The armature of the elevator motor is designated Mand its separately excited field winding MF. A resistance RG is providedfor controlling the strength of the generator separately excited fieldand therefore the voltage applied to the elevator motor armature. RM isa cooling resistance for the motor field winding MF while RB is acooling resistance for the brake release coil BR.

The contacts operated by the car door and engaged when this door isclosed are designated GSi and GS2. The door contacts operated by thevarious hoistway doors are arranged in series relation. Those contactsare not closed until the doors are closed and locked. For conveniencethe hoistway door contacts are shown as a single I pair of contactsdesignated DL. The car door and hoistway doors are shown in Figure 1 andcircuits are shown in Figure 3 for effecting their opening and closingby power. The door operating mechanism is not shown but may be of thetype shown in Patent No. 1,922,708 to Clifford Norton, granted August15, 1933. DOL and DCL are respectively the door open limit switch andthe door close limit switch of the door operating switch contacts. Thearmature of the advancer and positioned at the first floor.

motor is designated AMA. This motor has two field winding portionsdesignated AMP! and AMF2.

It will be assumed that the car is out of service When the car lastarrived at the first floor, brush DB engaged stationary contact LTCcompleting a circuit from feed line 3+ 150 through the brush andcontact, resistance RDX2, contacts DGX3, set coil of direction holdingswitch DG, contacts H2 and contacts EXZ, to line B. This caused theoperation of switch DG which latched in operated condition. Thus whenthe car is placed back in service switch DG is in operated condition.

The car is returned to service by restarting the motor generator set,and closing service switch IS. The closing of switch IS renderseffective the car buttons and other controls individual to the car. Thehall buttons, being common to all cars, remain efiective when the car isout of service. The closing of service switch IS also causes suficientvoltage to be applied to the position indicator lamp PC l for the firstfloor to cause this lamp to become illuminated. The circuit is from lineB+150 through resistance RACC, contacting portion of cam CX, hook switchHXl, lamp PCl, resistance RPC, to voltage divider RDV3. vThe lighting ofthis lamp indicates that the car is at the first floor. Assuming thatthe voltage of supply lines and of Figure 4 is from an exciter driven bythe motor generator set, the starting of the motor generator set causesthe elevator motor field winding ME to be energized to a standing fieldvalue. Also, brake resistance switch BK is operated to cause, throughthe engagement of contacts BKi, relay XA to be operated. Switch BK alsoengages contacts 3K2 to short circuit resistance RB in series with thebrake release coil BR. As brush ADB is in engagement with stationarycontact ALC, highest call light switch HLS also is operated. Further, ascontacts DGl3 are engaged, switch DGX is operated, this switchseparating contacts DGX3 to disconnect the set coil of switch DG fromthe lines, inasmuch as this switch is latched in operated condition. Thedoors may be either parked open or parked closed. The circuits areillustrated for parked open condition although the same circuits may beutilized for parking the doors closed. In the eventthe doors were parkedclosed, it would be desirable to have in parallel with contacts S03. aswitch which is temporarily closed in starting the motor generator set.This, as will be seen from later description, would cause operation ofdoor open switch D0 to effect the opening of the doors and thus enablethe attendant to enter the car.

To start the car, the attendant touches start button SB. It is to benoted that the anodecathode circuit for the tube of this button is fromA. 0. feed line A0 I through the tube and the coil of running switch KRto feed line 3-50. Thus volts of alternating current are being appliedto the tube which is insufficient to break it down.

13 However, when the attendant touches the start button, a circuit is tovoltage divider RDV5, the secondary of transformer TF3 to line B+70,thence to voltage divider RDVI and through voltage divider RDV2 to lineB-50, thence through the secondary of transformer TFI to line AC! andthus to the anode of the tube, and thence from the tube envelope throughthe body of the attendant back to ground. This causes suflicient voltageto be applied across the envelope and anode of the tube to alter thefield pattern of the tube sutficiently to cause the tube to break down.When the tube fires, it becomes illuminated, indicating that the controloperation is being performed. As soon as the tube fires, the voltageacross its anodecathode drops to sustaining value with the result thatsufficient voltage is applied to the coil of running switch KR. to causethis switch to operate. Rectifier VKR acts to sustain the current in thecoil of switch KR during the negative portion of alternating currentcycle.

Upon the firing of the tube of button SB, sufficient voltage is appliedacross the control electrode and cathode of the tube of the door closebutton DCB to cause this tube to fire. When it fires, the tube becomesilluminated to indicate that its control operation is being performed.This in turn causes suflicient voltage to be applied to the coil of doorclose switch DC to cause this switch to operate. The circuit for thecoil of switch DC is from line ACI through the anode and cathode of thetube of button DCB, contacts HI, contacts DOI, coil DC and limit switchDCL to line B50. The rectifier VDC acts to sustain the energization ofthe coil of switch DC during the negative portion of the alternatingcurrent cycle. Switch DC operates to initiate the closing of the firstfloor hoistway door and car door by contacts not shown. It also engagescontacts DCI to complete a circuit for the operating coil of pawl magnetPM through contacts EX4. The pawl magnet operates and becomes latched inoperated condition. Upon operation it retracts the pawls to clear thestopping collars and in doing it engages contacts PM3 which completes acircuit from line through contacts DG1, armature AMA and field windingAMF2 of the advancer motor and contacts KRI, closed as the result of theoperation of switch KR. Thus the advancer motor operates to advance thecarriage in the up direction as the closing of the doors takes place.

During the advance of the carriage, selector switches ILS and 3L8 areclosed and selector switch ZLS is opened. The closing of switch 3L8completes a circuit switch EX through contacts DDI and contacts SS3.Switch EX separates contacts EX4 to disconnect the pawl magnet operatingcoil, inasmuch as the pawl magnet is latched in operated condition. Alsothe brushes, switch and cam carried by the advancer panel are advancedby movement of the carriage. This includes brush ADB which leavescontact ALC, breaking the circuit for the coil of switch HLS. Thisswitch upon dropping out engages contacts HIS! which completes a circuitfrom line B+150 through the tube of button URB, contacts DGG, contactsHLSZ and resistance RUR2 to line ACI. alternating current superimposedon 200 volts of direct current are applied to this tube which causes thetube to break down, resistor RDXZ being disconnected at contacts DGXIfrom across the tube at this time to insure the tube breaking down. Theillumination of this tube serves to established from ground GR for thecoil of auxiliary speed Thus 110 volts f- 1 indicate that the car is totravel in the up direction.

The doors may be closed without initiating the starting of the car bythe attendant touching door close button DCB instead of start button SB.This causes the tube of button DCB to fire as a result of the connectionthrough the attendant to ground, in the same manner as the start buttontube is fired by touch as above del'll scribed. The breakdown of thedoor close button tube causes the operation of the door close switch DCto initiate the closing of the doors.

Regardless of whether closed by button SB or button DCB, as the doorsreach closed position,

door close limit switch DCL opens to break the circuit for the coil ofdoor close switch DC with the result that the tube of button DCB isextinguished and the door close switch drops out.

The doors, at any point during their closing or after they have beenclosed either by door close button DCB or start button SB, may bereopened by the attendant touching door open button DOB.

Where the doors have been closed by start button SB, the door openbutton is not efiective if the starting operation has progressed beyondthe point where switch E is operated and thus contacts El are separated.It is to be noted that .,a circuit exists from line B+l throughresistance RDOI, the tube of door open butt-on DOB, coil of door openswitch DO, contacts El, door open limit switch DOL, and contacts S02 toline B. This voltage, however, is not sufiicient to break down the tube.When the attendant touches button DOB, a. circuit is established fromground to voltage divider RVD5, the secondary or transformer TF3 to lineB+70, thence through half of voltage divider RDVI to line B+150 which isconnected through resistor RDOI and coil of switch D0 to the anode ofthe tube, and thence from the tube envelope through the body back toground. As a result, suflicient alternating current voltage is appliedbetween the anode and the tube envelope to break down the tube. When thetube fires, it becomes illuminated to indicate that its controloperation is being performed. The firing of the tube causes operation ofthe door open switch D0 which engages contacts not shown to effect theopening of the doors. It also separates interlock contacts DOI in thecircuit for the coil of door close switch DC, and engages self-holdingcontacts D02. As the doors reach open position, door open limit switchDOL opens to break the circuit for the coil of switch DO. As a result,the tube is extinguished and switch DO drops out.

It is to be noted that the anode-cathode ciredit of the tube of buttonDOB is connected across lines 3+ 150 and B so that this tube once firedis maintained conducting, enabling the attendant to remove his fingerfrom the button. However, in the case of buttons SB and DCB, theanodecathode circuit of each tube is connected across the secondary oftransformer TFI so that the tube is not maintained conducting when thetouch is discontinued. Thus to maintain these buttons effective theattendant holds his finger in contact with the button. This arrangementis preferred for reasons of safety in connection with the operation ofthe doors.

It will be assumed that the attendant initiates the starting of the carand the closing of the doors by touching start button SB. As the doorsreach closed positions car door contacts GSI and GS! engage and thefirst floor h'oistway door contacts engage so that door contacts DLclose. As-

attendants aceaaea the coil of field and brake switch H, selectorcontacts ILS, contacts DGli, coil of up direction switch UD, contactsssi, contacts DL, contacts GSI and contacts KR2 to line upon operationengages contacts H5 in short circuit resistance RM in circuit with theelevator field winding MF, bringing this strength. Switch H also engagescontacts H6 which completes a circuit for the release coil BR. of theelectromechanical brake. It also separates contacts H-S to disconnectgenerator field winding GF from across the generator armature. At thesame time switch UD engages contacts UD2 and UD3 to connect thegenerator field windingto lines and The completion of the circuit forthe generator field winding causes current to be supplied from thegenerator armature G to the motor armature M and, the brake beingreleased as the result of the energization of its coil, the elevatormotor starts the car in the up direction.

The brake, upon being released, efi'ects the separation of contacts BRIwhich breaks the circuit for the coil of brake resistance switch BK.This switch drops out to separate contacts BKZ, inserting coolingresistance RB in circuit with the brake release coil. It also separatescontacts BKI to break the circuit for the coil of speed switch timingrelay XA. Relay XA is delayed in dropping out by the discharge ofcondenser QXA. Upon dropping out it engages contacts XAI which completesa circuit for the coil of speed switch E. This circuit is from linethrough contacts XAI, contacts H3, coil E, switch 3L8, contacts DDI andcontacts SS3 to line Switch E upon operation separates contacts E! torender door open button DOB ineffective. It also engages contacts E2 tocomplete a circuit through car door contacts GSZ for the coil ofoperating sequence switch S0. Switch SO upon operation engages contactsS04 to establish a self-holdin circuit. It also engages SOI to establisha shunt circuit through resistance R83 and rectifier VSB for the tube ofbutton SB, causing this tube to be extinguished. The discontinuance ofthe illumination advises the attendant that the may now remove hisfinger from the start button, switch KR. being maintained operated byway of this shunt circuit. Switch E also engagescontacts E3 to shortcircuit a portion of resistance RG 1 in circuit with generator fieldwinding GF. This increases the voltage applied to the generator fieldwinding to a value to cause the generator voltage to build up to fullvalue and thus to bring the elevator car up to full speed.

Assume that before the starting of the car from the first fioor isinitiated two passengers enter the car and announce the second and thirdfloors as'their destinations. The attendant thereupon touches carbuttons C2 and C3. This causes their tubes to break down, the circuit ineach case being from the tube envelope through the attendants body toground, thereby applying alternating current voltage obtained fromtransformer TF3 across the tube envelope and anode, the circuit beingsimilar to that traced for the door open button DOB. As soon as thetubes break down, they become illuminated to indicate that the calls areregistered and the attendant may then discontinue the touch, the tubesbeing maintained conductive by the voltage from across line B+150 toline B. Also. when the tubes become conductive Switch H field up to fulla potential drop exists across the load resistors for these tubes,namely, resistors RC2 and RC8. This causes potential to be applied tothe control electrode of highest call return tube HCR, the circuit inthe case of the third floor car button for example being from aconnection between the cathode of tube C3 and resistance RC3 throughhook switch ma, rectifier VC3, hook switch HC3, hook switch\ HCT,rectifier VHC and resistor RHCP to the controlelectrode. Thus voltageequal to the potential drop across resistor RC3 plus the potentialdifference between line B and line B-.-50 is applied across the controlelectrode and cathode of tube HCR, 'which causes this tube to break downbetween anode and cathode. The anode-cathode circuit of this tube isfrom line ACi through contacts HRS, coil HJ, the anode and cathode ofthe tube to line 3-50. When the tube fires sufiicient voltage is appliedto the coil of highest call switch HJ to cause this switch to operate,rectifier VHJ acting to sustain the current in the coil during thenegative portion of the alternating current cycle. Relay HJ uponoperation engages contacts -HJi which causes the tube of button URB tobreak down immedi ately, the illumination of this tube thus also servingto indicate that a call exists above the car.

Relay HJ also separates contacts H32, preventing moved out of thetrough, opening the switch.

the completion of a circuit for the coil of highest call reversal switchHR upon the engagement of contacts H1S3 incident to the starting of thecar.

Upon the engagement of the conducting portion of cam CY with hook switchH02, a circuit is completed from the connection of the cathode of thetube of button C2 and. load resistor RC2 through hook switch HX2,rectifier VC2, hook switch H02, cam CY and resistor RCPP to the controlelectrode oftube CCP. As explained in connection with tube HCR thisapplied voltage equal to the potential, drop across resistor RC2 plusthe potential difierence between line B and line 3-50 across the controlelectrode and cathode of tube CCP. This places the tube in condition tobreak down between anode and cathode upon the completion of itsanode-cathode circuitr At this time the operating roller of switch S1 isin engagement with the lower side of the trough of second floor cam T02,causing this switch to be open. Shortly thereafter the roller rides intothe trough of the cam causing the momentary closing of switch SI. Thiscompletes the anodecathode circuit for tube GOP and, owing to the factthat the conducting portion of cam CY is of a length not to run ofiswitch HCZ so that voltage is still applied across the control electrodeand cathode of the tube, causes the tube to break down from anode tocathode. The circuit for this tube is from line E+ through switch SI,contacts EXi, contacts PM2, pawl magnet reset coil PM, the anode andcathode of tube GOP and resistance RCPP to line B-50. When the tube thusbreaks down, suiiicient voltage is applied to the reset coil of the pawlmagnet to cause the pawl magnet to be reset. The reset of the pawlmagnet releases the pawls and separates contacts PM! and PMS. Theseparation of contacts PME breaks the circuit for the reset coil of thepawl magnet and the anode-cathode circuit for tube CCP while theseparation of contacts PM3 deenergizes the advancer motor AM.

As the car and therefore the crosshead move upwardly the up pawl engagesthe second floor stopping collar bringing the carriage to a stop. Also,at this time the roller of switch SI has Continued movement of thecrosshead causes the opening of selector switch 3L8, the closing ofselector switch ZLS and the opening of selector switch ILS in the ordernamed as the car comes to the second floor. The opening of selectorswitch 3L5 breaks the circuit for the coils of switches E and EX. SwitchE drops out to separate contacts E3 which reinserts resistance RG incircuit with the generator field windin GF. This decreases the voltageof the generator causing the car to slow down. Switch E also engagescontacts El in preparation for the automatic door operation.

The circuit for automatically initiating the opening of the doors iscompleted upon the engagement of contacts ZLS just before the carreaches the second floor. This circuit is from line B+150 throughresistor RDOI, the tube of button DOB, coil DO, contacts El, switch DOL,contacts ZLS, contacts 503 and resistor RDO2 to line ACI. This causes110 volts of alternating current superimposed upon 200 volts of directcurrent to be applied across the anode-cathode of this tube which causesthe tube to break down. Thus the door opening switch D is operated tocause the opening of the car door and second floor hoistway door in themanner previously described. The engagement of contacts D02 transfersthe circuit of coil DO and the tube from line ACl to line B and thusmaintains the door opening operation during the interval between theseparation of contacts S03 and the engagement of contacts S02 as aresult of the opening of car door contacts GS2 in the door openingoperation.

The opening of switch ILS, which occurs as the car arrives at the secondfloor, breaks the circuit for the coils of switches H and UD. Switch UDseparates the contacts-UB2 and UD3 to break the circuit for thegenerator field winding GF, while switch H separates contacts H4 tobreak the circuit for release coil BR of the electromechanical brake.Thus the excitation of the generator is discontinued and the brake isapplied to bring the car to a stop at the second floor. At the same timeswitch H engages contacts H6 to reconnect field windin GF across thegenerator armature and separates contacts H to reinsert resistance RM incircuit with elevator motor field Winding MF. Contacts HI of switch Hprevent the initiation of the reclosing of the doors and the restartingof the car, as by maintaining touch on button SB, until the car has beenbrought to a stop.

As the car arrives at the second floor, the conducting portion of cam CXengages hook switch HXZ which establishes a shunting circuit throughresistor RACC for the tube of button 02. This raises the cathodepotential of this tube, causing the tube to be extinguished and thusautomatically cancelling the second floor car call. Also, the engagementof this conducting portion of cam OK with this hook switch completes acircuit for the second floor car position indicator lamp PC! causingthis lamp to become illuminated to indicate that the car is positionedat the second floor.

After the passenger has been discharged at the second floor, the doorsare reclosed and the car started as before by the attendant touchingstart button SB. The advance of the carriage is for up car travel andthe car is started in the up direction inasmuch as switch DG remainslatched in operated condition.

Upon the engagement of the top insulated portion of cam CY with bookswitch HC3, the

tact HL3 so that contacts HLC are in engagement. This maintains thevoltage across the control electrode and cathode of tube HCR, the

- circuit to the control electrode being from line 3+ through contactsHLC, rectifier VHH and resistance RHCP. Thus tube HCR is maintainedconductive and switch HJ is maintained operated.

Upon the engagement of the conducting portion of cam CY with hook switchH03, voltage is applied across the control electrode and cathode of tubeCCP as previously described. At the same time brush BHL engagesstationary'contact HL3 causing the opening of contacts HLC todiscontinue the application of voltage across the control electrode andcathode oi. tube HCR. Inasmuch as alternating current is being suppliedto this tube, the tube goes out and this switch HJ drops out. Upondropping out, switch HJ engages contacts HJ2 which completes a circuitthrough contacts PM4, contacts EX! and contacts HLS 3 for the coil ofhighest call reversal switch HR. Switch HR engages contacts HRS toestablish a self-holding circuit and also engages contacts HR4 in acircuit through contacts DGI and resistor RPM for the reset coil of thepawl magnet. Upon the closing of switch SI, as its roller runs into thetrough of cam T03, a circuit is completed for the pawl magnet reset coilthrough resistance RPM, contacts DGl and contacts HR I. Tube CCP mayalso break down from anode to cathode depending upon the value ofresistance RPM. The energization of the reset coil of the pawl magnetcauses the car to be slowed down and brought to a stop at the thirdfloor and the third floor hoistway door and car door to be automaticallyopened in themanner above described. The third floor car call isautomatically cancelled and the third floor position indicator lamp P03is illuminated as the car comes to the floor, also as above described.

Contacts EXZ reengage at the initiation of the slow down and contacts H2reengage as the car is brought to a stop at the third floor, whereupon acircuit is completed for the reset coil of direction holding switch DG,this circuit being from line B+150 through contacts HLSI, contacts HRS,resistance RDXI, contacts DGX2, reset coil of switch DG, contacts H2 andcontacts EX! to line B. This causes switch DG to be reset. Upon beingreset switch DG engages contacts DGi to place sufilcient potential onthe control electrode of the tube of button CI to cause this tube tobreak down, thus automatically registering a. car call for the firstfloor. rates contacts DGIU and engages DGII to set the car for down cartravel. It also separates contacts DGS to extinguish the tube of buttonURB and engages contacts DG5 to establish a circuit for the tube ofbutton DRB from line B+150 through the tube, contacts DG5 and resistorRDR2 to line ACI, causing this tube to break down, ressitor RDXI beingdisconnected from across the tube by separation of contacts DGXI. Thus avisual indication is provided that the car 'is set for down direction oftravel. It also engages contacts DGB to reestablish the circuit for thecoil of highest call light switch HLS, causing this switch to operate.It also engages contacts DGI2 to by-pass contacts HLSI and HJ2 tomaintain switch HR operated. It also separates contacts DG|3 to breakthe circuit It also sepa 19 for the coil of auxiliary direction switchDGX which drops out. The resultant separation of contacts HLSI andcontacts DGX2 breaks the circuit for the reset coil of switch DG, switchDG remaining in reset condition.

After the passenger has been discharged at the third floor, the doorsare reclosed and the car started as before by the attendant touchingstart button SB. However, owing to the fact 'that the switch DG is nowreset and the car is set for downward travel, the carriage is advancedin the direction for down car travel and the car is started in the downdirection. The downward advance of the carriage is due to the fact thatcontacts DG'I are separated and contacts DGB are engaged wherefore thecircuit for the advancer motor is through field winding AMFI instead ofthrough field winding AMF2. The starting of the car in the downdirection is due to the fact that contacts DGlll are separated andcontacts DGII are engaged so that, upon the closure of the third floorhoistway door and car door to cause the engagement of door contacts DLand car door contacts GSI, a circuit is completed for the coil of downdirection switch DD along with the coil of switch H. Thus switch DDengages contacts DB2 and DD3 so that the polarity of generator fieldexcitation is such that the car is started in the down direction. Uponthe engagement of the conducting portion of cam CY with hook switch HCIas the car approaches the first fioor, voltage is applied across thecontrol electrode and cathode of tube CCP so that upon the closing ofswitch SI as its roller runs into the trough of cam TCI, the reset coilof the pawl magnet PM is energized to effect the reset of the pawlmagnet. As a result, the down pawl engages the first floor stoppingcollar, bringing the carriage to a stop and opening the selectorswitches to cause the slowing down and stopping of the car at the firstfloor and the automatic opening of the doors as previously described.Also terminal stopping switch contacts SSI and SS2 open to assure theslowing down and stopping of the car at the first floor. fioor car callis reset and the first floor car position indicator lamp PCI isilluminated as the car arrives at the first floor due to the engagementof the conducting portion of cam OK with hook switch HXl As the car isbrought to a stop, contacts H2 reengage which completes a circuitthrough brush DB and contact LTC for the set coil of switch DG, thiscircuit having been previously traced.

Switch DG, upon operating, engages contacts DGI3 which completes acircuit for the coil of switch DGX, condenser QDGX and resistance RDGXacting to delay the operation of this switch sufilciently to insure thatswitch DG is operated and latched in operated condition before contactsDGX3 separate. The operation of switch DG sets the car for travel in-theup direction and extinguishes the tube of button DRB. Also switch HLS ismaintained operated after the separation of contacts DG9 owing to thefact that brush ADB is in engagement wtih contact ALC with the car atthe first floor.

Assume now that before button SB is touched to start the car from thefirst fioor, an intend-v ing passenger at the second floor wishing to becarried in the up direction touches one of the up landing buttons, forexample button U2. The touching of this button causes the tube of thisbutton to fire in the same manner that the tubes of the car buttons werecaused to fire as previ- The first 20 ously described, the circuit beingfrom the envelope of the tube back to the ground through the body of theintending passenger. It is to be noted that before this tube fires thepotential of its control electrode with respect to its cathode and thatof the control electrode wtih respect to the cathode of the tube of thecorresponding across the corridor button U2 is 30 volts negative. This,however, is not suificient to cause the tubes to break down. However,when either tube does break down due to touch, that of button U2 in theexample being discussed, the potential of the cathode of this tube risesan amount equal to the potential drop across load resistor RUZ, whichcorrespondingly raises the cathode potential of the tube of button U2.This increases the difierence in potential between the cathode andcontrol electrode of the tube of button U2 to an amount equal to 30volts plus the potential drop across resistance RU2 which is sufficientto fire this tube, equalizing resistors RUE2 and RUEZ' enabling thesetwo tubes to be conductive in parallel. Thus upon the touching of onebutton to register a call, both tubes fire, providing a visualindication on both sides of the corridor that the call has beenregistered.

As regards operations performed by these tubes in addition to the callregistration indications, inasmuch as their cathodes are connecteddirectly in parallel, the tubes act as one. The potential drop acrossload resistor RUZ plus 30 volts obtained from voltage divider RDV2 isapplied to tube WPUZ which serves as up second fioor waiting passengerindicator, causing this tube to break down and thus become illuminatedto indicate that an up call has been registered at the second floor.Also a potential above line B equal to the voltage drop across loadresistor RUZ is placed on selector contacts SU2. Also this results in avoltage equal to the potential drop across resistor RU2 plus thepotential difference between line B and line B50 being applied acrossthe control electrode and cathode of tube HCR. This circuit is from theconnection between load resistor RU2 and the cathodes of the tubes ofbuttons U2 and U2 to contact SU2, rectifier VU2, rectifier VHL2, contactHLI, brush BHL, rectifier VHLC, rectifier VHH and resistor RHCP to thecontrol electrode of tube HCR. The firing of tube HCR causes theoperation of switch HJ. Switch HJ engages contacts HJ I causing the tubeof button URB to fire to indicate that a call exists above the car. Italso separates contacts HJ2 to prevent the energization of the coil ofswitch HR. Potential is also placed on selector stationary contacts SUM,etc., for all other elevators but as to whether tube HCR for any otherelevator is fired due to the registration of this call depends onwhether the car is set for up travel and the position of brush BHL forthat elevator.

Assume further that before button SB is touched to start the car, anintending passenger at the third fioor wishing to be carried in the downdirection touches one of the down landing buttons, for example D3. Thiscauses the tubes of both down landing buttons D3 and D3 to fire asdescribed in connection with the firing of the tubes of up landingbuttons U2 and U2. This applies a voltage equal to the potential dropacross load resistor DR3 plus 30 volts obtained from voltage dividerRDVZ to tube WPD3. This causes this tube to break down and thus providesvisual indication that a down call has been registered at the thirdfloor. Also potential is accaaac 21 placed on selector contact SD3,SD3a, etc., for each elevator and an additional circuit is provided forapplying potential to the control electrode of tube HCR, HCRa, etc. foreach elevator,

this circuit for tube HCR being from the left,

hand side of load resistor RD3 to contact S133 through rectifier V133and thence by way of rectifier VHL2 to the control electrode of tubeHCR, as previously traced.

Assume that the starting of the car is initiated. Potential ismaintained on the control electrode of tube HCR and thus the tube ismaintained conductive during movement of brush BHL betweenHL contacts bycontacts HLC as previously described. Upon engagement of brush BU withcontact SU2, voltage equal to the potential drop across resistor RU2plus the potential difference between line B and line B- is appliedacross the control electrode and cathode of tube LCP. Upon the closingof switch $1 the anode-cathode circuit of this tube is completed causingthe tube to break down from anode to cathode and reset the pawl magnet.The circuit is similar to that previously traced for tube CCP. Thiscauses the car to be slowed down and stopped at the second floor, aspreviously described.

As'the pawl magnet is reset at the initiation of the stop, contacts PMIengage to connect the control electrode of tube LCC to the cathodes oftubes of buttons U2 and U2. The circuit is from these cathodes tostationary contact SU2, brush BU, contacts HR2, contacts XYI, contactsPMI, resistor RLGP and the secondary of transformer TF4 to the controlelectrode. The anode and cathode of tube LCC are connected acrossresistor RLCDI which with resistor RLCDZ forms a voltage dividerconnected across lines 3-50 and AC4. Thus 105 volts alternating currentsuperimposed on 120 volts direct current are opplied to the voltagedivider and, as resistor RLCDI is about three times the ohmic value ofresistor RLCD2, about three-quarters of this voltage is applied acrossthe anode-cathode of tube LCC. With contacts PMI separated. the controlelectrode of this tube is connected to the cathode through the secondaryof transformer TF4, the voltage of this secondary being in phase withthat of the secondary of transformer TF3. This places the controlelectrode 40 volts above the cathode potential. Thus with contacts PMIseparated the voltage values are such that tube LCC does not break down.However upon the closing of contacts PMI, the cathode potential of thetubes of buttons U2 and U2 is placed on the control electrode of tubeLCC. The control electrode potential is thus raised to a point which,with the alternating current voltage from transformer TF4 superimposedthereon, is suiiicient to cause tube LCC to fire. This raises thecathode potential of tube LCC to a value tube drop below the anodepotential. Due to blocking rectifier VLC permitting the flow of currentfrom the cathode of tube LCC to the cathodes of the tubes of buttons U2and U2, the potential of the cathodes of these latter tubes is raisedwith respect to their anodes, causing these tubes to be extinguished.Condensers QU2 and QU2' enable the potential of the control electrodesof the tubes of buttons U2 and U2 to be raised along with the cathodesto assist in extinguishing the tubes. Thus the up call at the secondfloor is automatically cancelled immediately the stop is initiated,preventing any other car answering the call. The cancelling of the calldrops the potential of the cathodes of tubes U2 and U2 to that of lineB. As a result, tube LCC is extinguished during the negative portion ofdrop out.

the alternating current cycle and does not reflre. obviating thestopping of another car due to the connection of the cathode of tube LCCthrough brush BU to selector contacts SU2 of the various elevators. Uponcancelling of the up second floor call, the application of voltage tothe waiting passenger indicator lamp WPU2 isdiscontinued so that thislamp is extinguished when the call is answered.

For convenience it will be assumed that no passenger enters the car atthe second floor and therefore that no car call is registered. Brush BHLas it moves upwardly touches the stationary contacts for the successivefloors to ascertain whether or not potential is applied to thesecontacts. Thus, upon the engagement of brush BHL with contact HL2 forthe second floor, potential was found on this contact due to the factthat an up call was registered at the second floor and a down call isregistered at the third floor so that potential was maintained on thecontrol electrode of tube HCR upon the separation of contacts HLC as theengagement of the brush with the stationary contact took place. When theup second floor call was cancelled, the potential was maintained due tothe third floor down call. However, upon the engagement of brush BHLwith stationary contact HL3 incident to the car proceeding from thesecond floor to the third floor (assuming button SB has been touched toinitiate restarting of the car),

; no potential is found on this contact inasmuch as no up call isregistered for the third floor and no landing call is registered for thefourth floor, rectifier VHL3 blocking the flow of current from theconnection from load resistor RD3 through rectifier VD3. Thus upon theseparation of contacts HLC, potential is removed from the controlelectrode of tube HCR which remains extinguished after the negativeportion of the alternating current cycle, permitting switch HJ to SwitchHJ engages contacts HJ2 which completes a circuit for the coil of switchHR as previously traced. Switch HR operates to become self-holding andseparates contacts HRZ and engages contacts HRI, rendering up brush BUineffective and down brush BD effective. Upon closing of switch SI acircuit is established for the reset coil of pawl magnet PM throughcontacts HR4. Also tube LCP may be caused to break down from anode tocathode inasmuch as the engagement of contacts HRI places potential fromresistor RD3 by way of contact SD3 and brush BD on the control electrodeof this tube. The reset of the pawl magnet causes the car to be sloweddown and stopped at the third floor in the manner previously described.Also the engagement of contacts PMI causes the down third floor call tobe automatically cancelled, the circuit to the control electrode of tubeLCC being by way of contact SD3, brush BD and contacts HRI.

Owing to contacts HR5 being engaged, a circuit is completed for thereset coil of switch DG as the car comes to a stop to set the car fordownward travel, as previously described.

Again for convenience it will" be assumed that no passenger enters thecar at the third floor and therefore that no car call is registered.Instead, it will be assumed that the car is again at the first floor andthat instead of a down call The cancelling of this call prevents itsbeing answered by another car.

